NAME
hardclock —
real-time timer
SYNOPSIS
void
hardclock(struct
clockframe *frame);
DESCRIPTION
Thehardclock()
function is called hz(9) times per second. It implements the real-time system
clock. The argument frame is an opaque,
machine-dependent structure that encapsulates the previous machine state.
The
hardclock()
performs different tasks such as:
- Run the current process's virtual and profile time (decrease the
corresponding timers, if they are activated, and generate
SIGVTALRMorSIGPROF, respectively). - Increment the time-of-day, taking care of any ntpd(8) or adjtime(2) induced changes and leap seconds, as well as any necessary compensations to keep in sync with PPS signals or external clocks, if support for this is in the kernel (see options(4)).
- Schedule softclock interrupts if any callouts should be triggered (see callout(9)).
SEE ALSO
adjtime(2), ntp_adjtime(2), signal(7), ntpd(8), callout(9), hz(9)